Researchers at Duke University in North Carolina have created a working Brain-Machine Interface (BMI) on a monkey brain. Mounted in a wheelchair, the monkey learned to control the wheelchair with his mind, in order to get the shortest route to a bowl of grapes. In three to six weeks, the monkey's driving skills significantly improved, and they managed to speedup their grape-task from 43 to a whopping 27 seconds. Interestingly, they recorded some differences in the brain when at the task, soms neurons became more strongly tuned to the distance between the wheelchair and the grapes. Read more interesting details about the experiment at the Guardian.